According to the pain ladder model of the World Health Organization opioids are indicated for the treatment of moderate to severe pain. Opioids for pain treatment are commonly administered as prolonged release pharmaceutical compositions, which are taken continuously e.g. on a 12 hour regimen.
However, opioid treatment can elicit side effects of which the most troublesome include opioid bowel syndrome and in particular opioid induced constipation. It has been reported that up to a third of patients reduce or discontinue opioid treatment as a consequence of problems with constipation (Bell et al., Pain Med 2009, 10, 35-42).
There is thus a continuing need for efficient pain treatment with opioids. There is also need for formulations that do not exhibit a food effect, which is one of the problems that the present invention seeks to solve.